1. Field of the Invention
The present invention relates to a method of manufacturing a laminated body and a laminated body which has electrodes on both surfaces of an insulating film, for example.
2. Background Art
Due to outstanding progress in information technology, information is at present frequently transmitted and received using a notebook-type personal computer, a mobile information terminal, or the like. Accordingly, it is a well-known fact that a ubiquitous society in which the information can be transmitted and received at any place is approaching in the near future. In the ubiquitous society, there is a demand for a lighter and thinner information terminal.
At present, a mainstream of a semiconductor material is a silicon type, and as a method of manufacturing thereof, a photolithography method is generally used.
On the other hand, attention has been paid to printable electronics in which an electronic member is manufactured using printing technology. There are merits that the printable electronics reduce costs relating to an apparatus and manufacturing more than the photolithography method by using printing technology, and since there is no requirement for a vacuum or high temperature, a plastic substrate can be used.
In printable electronics, as a semiconductor material, an organic semiconductor which is soluble in an organic solvent or the like is generally used. This is because a semiconductor layer can be formed by a printing method.
As a method of using an organic semiconductor which is soluble in an organic solvent or the like as a semiconductor material, for example, there is a technology disclosed in JP-A-2005-210086. In JP-A-2005-210086, an organic semiconductor layer is formed by an ink jet method. Here, a TFT using an organic semiconductor is referred to as an organic TFT.
As members configuring a TFT, there are an electrode and an insulating film other than a semiconductor. However, there is a demand for an electrode and an insulating film to be formed using a wet method such as a printing method and a coating technology to form a TFT with low costs.
As a technology that forms an electrode and an insulating film using a wet method, for example, there are technologies disclosed in JP-A-2004-297011 and JP-A-2007-266355. In JP-A-2004-297011, an electrode is formed by an ink jet method and in JP-A-2007-266355, a gate insulating film is formed by a spin coat method.
Here, for example, when a display or the like is driven by using an organic TFT, the gate insulating film is usually formed to have a thickness of 1.0 μm or less in order to obtain a driving voltage and a desired current value.
However, tiny protrusions are locally formed in the electrodes formed by the technologies as described in JP-A-2004-297011 and JP-A-2007-266355 in some cases. Moreover, a locally thick film portion caused by cohesion of ink and foreign substances originating from the environment and processes are often present in the electrode formed by a wet method other than protrusions.
In this case, when the gate insulating film is formed by the wet method, a difference in wettability is generated with respect to other portions due to foreign substances present in the electrode in a part of the gate insulating film and there is a possibility of forming a portion which is not covered by the gate insulating film in the electrode (hereafter, referred to as “lower electrode”).
In the wet method such as a spin coat method, since the shape followability to an underlying layer becomes worse in comparison with a dry method such as a sputtering method, and when protruding objects or foreign substances are present in the lower electrode, there is a possibility of forming a portion which is not covered by the gate insulating film in the lower electrode.
Then, in a state in which the portion which is not covered by the gate insulating film in the lower electrode is formed and in a state in which an electrode (hereafter, referred to as “upper electrode”) is laminated on the gate insulating film, since the lower electrode comes into contact with or comes close to the upper electrode, there is a possibility that a short circuit and a leakage can be generated between the lower electrode and the upper electrode.
Therefore, when the electrode or the gate insulating film is formed by the wet method, there is a possibility that a short circuit and a leakage can be generated between the lower electrode and the upper electrode in a state in which the upper electrode is laminated on the gate insulating film.